Advertisement From May 1915 Issue Of Harper’s Bazaar

From The Straight Dope:

“…U.S. women were browbeaten into shaving underarm hair by a sustained marketing assault that began in 1915. (Leg hair came later.)… the underarm campaign began in May, 1915, in Harper’s Bazaar, a magazine aimed at the upper crust. The first ad ‘featured a waist-up photograph of a young woman who appears to be dressed in a slip with a toga-like outfit covering one shoulder. Her arms are arched over her head revealing perfectly clear armpits. The first part of the ad read “Summer Dress and Modern Dancing combine to make necessary the removal of objectionable hair.”‘”